SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75f01530bccb08dedc7b8b4413f91860fb5548e6959851d18b882b7a90b31c8f' 
  AND token = '1KY36ZGQ/89aFRJbg5wsJX0uUepzvkzy9nHmwzWpTmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}